The objective of the study is to assess the quantitative aspects and specificity of the effects of ethanol and other drugs on intravenous nicotine self-injection in rhesus monkeys. The first specific aim is to establish lever-press responding maintained by intravenous nicotine injections. The effects of variations in nicotine unit dose on behavior will then be examined. Subsequently, the effects of ethanol, caffeine, d-amphetamine, pentobarbital, mecamylamine, and hexamethonium on nicotine self-administration will be evaluated. Drug effects on nicotine self-injection will be compared with food reinforced responding within each animal. A fixed-ratio schedule of durg and food presentation will be used in the initial experiments. A second order schedule (a fixed-interval schedule of fixed-ratios) will later be used. Single and multiple dose pharmacokinetics of nicotine doses that maintain responding will be determined. Redeterminations will be made in the presence of behaviorally-active plasma concentrations of ethanol. Pharmacokinetic studies will enable us to detect peripheral drug interactions and allow correlation of ethanol plasma level and behavioral effect.